U.S. patent application number 16/341454 was filed with the patent office on 2019-12-12 for 3 dof parallel mechanism with 3 branched-chains.
The applicant listed for this patent is SHENZHEN INSTITUTES OF ADVANCED TECHNOLOGY CHINESE ACADEMY OF SCIENCES. Invention is credited to Yongfeng Wang, Jing Yang, Xiaojun Zhang, Guoru Zhao.
Application Number | 20190375117 16/341454 |
Document ID | / |
Family ID | 57865957 |
Filed Date | 2019-12-12 |
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United States Patent
Application |
20190375117 |
Kind Code |
A1 |
Wang; Yongfeng ; et
al. |
December 12, 2019 |
3 DOF PARALLEL MECHANISM WITH 3 BRANCHED-CHAINS
Abstract
The present disclosure relates to a robot, and provides a 3
degree-of-freedom parallel mechanism with 3 branched-chains, which
includes a fixed platform, a movable platform, and three arc-shaped
connecting rods. The rotation axes of three arc-shaped connecting
rods are intersected with each other and each rotation axes is
parallel to the fixed platform. Each arc-shaped connecting rod has
a sliding slot curved extending along a longitudinal direction. The
three connecting shafts one-to-one corresponds to the three
arc-shaped connecting rods and are disposed on the movable
platform. A first end of each connecting shaft is fixedly connected
with the movable platform. A second end is hinged joint with a
connecting head. The connecting head is slid and disposed in the
corresponding sliding slot.
Inventors: |
Wang; Yongfeng; (Shenzhen,
CN) ; Zhao; Guoru; (Shenzhen, CN) ; Yang;
Jing; (Shenzhen, CN) ; Zhang; Xiaojun;
(Shenzhen, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SHENZHEN INSTITUTES OF ADVANCED TECHNOLOGY CHINESE ACADEMY OF
SCIENCES |
Shenzhen |
|
CN |
|
|
Family ID: |
57865957 |
Appl. No.: |
16/341454 |
Filed: |
November 14, 2016 |
PCT Filed: |
November 14, 2016 |
PCT NO: |
PCT/CN2016/105727 |
371 Date: |
April 12, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25J 17/0266 20130101;
B25J 9/0045 20130101; B25J 9/0009 20130101 |
International
Class: |
B25J 17/02 20060101
B25J017/02; B25J 9/00 20060101 B25J009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2016 |
CN |
201610902874.5 |
Claims
1. A 3 degree-of-freedom (DOF) parallel mechanism with 3
branched-chains, comprising: a fixed platform, a movable platform
disposed above the fixed platform, and three arc-shaped connecting
rods; wherein the three arc-shaped connecting rods are all rotated
and connected with the fixed platform; the rotation axes of three
arc-shaped connecting rods intersect with each other and each
rotation axes is parallel to the fixed platform; each arc-shaped
connecting rod has a sliding slot curved extending along a
longitudinal direction; three connecting shafts one-to-one
corresponds to the three arc-shaped connecting rods and are
disposed on the movable platform; a first end of each connecting
shaft is fixedly connected with the movable platform; a second end
is hinged joint with a connecting head; the connecting head is slid
and disposed in the corresponding sliding slot.
2. The 3 DOF parallel mechanism with 3 branched-chains according to
claim 1, wherein a connecting head and a corresponding connecting
shaft are connected by a cross universal hinge.
3. The 3 DOF parallel mechanism with 3 branched-chains according to
claim 1, wherein two ends of each arc-shaped connecting rod are
fixedly connected with the fixed platform through a connecting
component; the two ends of each arc-shaped connecting rod are
rotated and connected with the corresponding connecting
component.
4. The 3 DOF parallel mechanism with 3 branched-chains according to
claim 3, wherein each connecting component comprises two supports
fixedly disposed on the fixed platform; the two ends of each
arc-shaped connecting rod are rotated and connected with the
corresponding support by a pin shaft.
5. The 3 DOF parallel mechanism with 3 branched-chains according to
claim 4, wherein a motor is disposed on one of the supports of the
corresponding connecting component, the pin shaft is driven to
rotate by the motor.
6. The 3 DOF parallel mechanism with 3 branched-chains according to
claim 4, wherein the two supports are oppositely disposed; the two
ends of each arc-shaped connecting rod are both disposed between
the corresponding two supports.
7. The 3 DOF parallel mechanism with 3 branched-chains according to
claim 1, wherein a movable platform is a flat cylindrical shape;
three connecting shafts are evenly distributed along the outer
circular surface of the movable platform.
8. The 3 DOF parallel mechanism with 3 branched-chains according to
claim 1, wherein three protrusions and the movable platform are
integrally formed; three protrusions one-to-one correspond to the
three connecting shafts; the connecting shaft is fixed and
connected with the corresponding protrusion.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to the robot field, in
particular to a 3 degree-of-freedom (DOF) parallel mechanism with 3
branched-chains.
BACKGROUND
[0002] Since a parallel robot was first proposed in 1938, a
parallel robot has been widely used in various fields of society
because of its large rigidity, strong bearing capacity, small
error, high precision, small self-weight load ratio, good dynamic
performance, and easy control, etc. At present, there is a common
parallel robot with 2 degree-of-freedom (DOF), 3 DOF, 4 DOF, or 6
DOF. The parallel mechanism with 3 DOF has symmetric distribution
of symmetrical branches and is most researched. It is applied in
the fields of machining rotary platform, rehabilitation device,
satellite positioning device, and installation device, etc.
[0003] For example, professor Feng Gao et al. of Yanshan University
proposed an offset output a 3 DOF spherical parallel mechanism with
a central spherical hinge (CN101306534), which has a typical
mechanism features 3-RRR to achieve three-direction rotation around
a fixed center. Professor Zhen Huang of Yanshan University proposes
a parallel mechanism with symmetrical structure and no accompanying
motion (CN102962840), which can continuous rotate in any axis or
any point on the middle symmetry plane of the fixed or movable
platform, and effectively avoid the occurrence of accompanying
motion. Long Shen of Shanghai University proposes a spherical 3 DOF
parallel mechanism antenna structure system (CN101924266), which
has a larger working space than the general 3 DOF spherical
mechanism. Rongfu Lin et al. of Shanghai Jiaotong University
proposed a 3 DOF spherical parallel mechanism with arc-shaped
sliding pairs (CN104827463), which uses the arc-shaped sliding
pairs, the movable platform rotates in three directions around the
arc-shaped midpoint is achieved.
[0004] Most kinematic pair configurations of these mechanism
branches mostly include RR or RRR. The axes of the kinematic pair
intersect at one point to achieve movement of 3 DOF of a movable
platform. Lin Rongfu of Shanghai Jiao Tong University uses
arc-shaped sliding pair. Thereby, the movable platform is bound by
forces from three directions through arc-shaped configuration of
the kinematic pair. It can only rotate in three directions around
an arc-shaped center. The motion is rather complication and the
control precision is not very high.
SUMMARY
[0005] The purpose of present disclosure is provided a 3
degree-of-freedom (DOF) parallel mechanism with 3 branched-chains
capable of overcoming the problem that the parallel mechanism
movement is complication and the control precision is not very high
in the prior art.
[0006] The present disclosure is achieved as follow:
[0007] The present disclosure provides 3 degree-of-freedom (DOF)
parallel mechanism with 3 branched-chains. Comprising a fixed
platform, a movable platform disposed above the fixed platform, and
three arc-shaped connecting rods. The three arc-shaped connecting
rods are all rotated and connected with the fixed platform. The
rotation axes of three arc-shaped connecting rods intersect with
each other and each rotation axes is parallel to the fixed
platform. Each arc-shaped connecting rod has a sliding slot curved
extending along a longitudinal direction. Three connecting shafts
one-to-one corresponds to the three arc-shaped connecting rods and
are disposed on the movable platform. A first end of each
connecting shaft is fixedly connected with the movable platform. A
second end is hinged joint with a connecting head. The connecting
head is slid and disposed in the corresponding sliding slot.
[0008] Furthermore, a connecting head and a corresponding
connecting shaft are connected by a cross universal hinge.
[0009] Furthermore, two ends of each arc-shaped connecting rod are
fixedly connected with the fixed platform through a connecting
component. The two ends of each arc-shaped connecting rod are
rotated and connected with the corresponding connecting
component.
[0010] Furthermore, each connecting component comprises two
supports fixedly disposed on the fixed platform. The two ends of
each arc-shaped connecting rod are rotated and connected with the
corresponding support by a pin shaft.
[0011] Furthermore, a motor is disposed on one of the supports of
the corresponding connecting component, the pin shaft is driven to
rotate by the motor.
[0012] Furthermore, the two supports are oppositely disposed. The
two ends of each arc-shaped connecting rod are both disposed
between the corresponding two supports.
[0013] Furthermore, a movable platform is a flat cylindrical shape.
The three connecting shafts are evenly distributed along the outer
circular surface of the movable platform.
[0014] Furthermore, three protrusions and the movable platform are
integrally formed. Three protrusions one-to-one correspond to the
three connecting shafts. The connecting shaft is fixed and
connected with the corresponding protrusion.
[0015] The present disclosure has beneficial effects as follow:
[0016] In the parallel mechanism of the present disclosure, the
movable platform is disposed above the fixed platform, and the
movable platform is connected with the fixed platform through the
three arc-shaped connecting rods. When one of the three arc-shaped
connecting rods is rotated relative to the fixed platform, the
other two connecting shafts is slid along the corresponding sliding
slot through the corresponding connecting shaft. Since the sliding
slot is an arc-shaped structure, the movable platform is overturned
in the air. The movable platform is relatively stable during
movement. The control precision is high, which avoids forming
accompanying movement during movement. The structure of the above
parallel mechanism is very simple and convenient to assemble.
BRIEF DESCRIPTION OF DRAWINGS
[0017] In order to clearly explain embodiment of the present
disclosure or technical scheme of the prior art. The drawings are
included to provide a further understanding of embodiments of the
present disclosure, which form portions of the specification and
are used to illustrate implementation manners of the present
disclosure and are intended to illustrate operating principles of
the present disclosure together with the description. Obviously,
the drawings in the following description are merely some of the
embodiments of the present disclosure, and those skilled in the art
are able to obtain other drawings according to the drawings without
contributing any inventive labor.
[0018] FIG. 1 is a structural schematic diagram of a 3
degree-of-freedom (DOF) parallel mechanism with 3 branched-chains
of an embodiment of the present disclosure.
[0019] FIG. 2 is a connecting structural schematic diagram of an
arc-shaped connecting rod and corresponding connecting component of
the 3 DOF parallel mechanism with 3 branched-chains.
[0020] FIG. 3 is a structural schematic diagram of the arc-shaped
connecting rod of the 3 DOF parallel mechanism with 3
branched-chains.
DETAILED DESCRIPTION
[0021] A technical proposal in the embodiments of the present
disclosure is clearly and completely described in the following
with reference to the drawings and embodiments. Obviously, the
described embodiments are only a part of the embodiments of the
present disclosure, but not all embodiments. All other embodiments
obtained by those skilled in the art based on the embodiments of
the present disclosure without creative efforts are within the
scope of the present disclosure.
[0022] As shown in FIG. 1, the present disclosure provides a 3
degree-of-freedom (DOF) parallel mechanism with 3 branched-chains,
which includes a fixed platform 1 and a movable platform 2 disposed
above the fixed platform 1. The fixed platform 1 is in a fixed
status. The movable platform 2 is moved relative to the fixed
platform 1. The parallel mechanism further includes three
arc-shaped connecting rods 3, which are all rotated and connected
with the fixed platform 1. The arc-shaped connecting rods 3 are
disposed on the fixed platform 1. Under action of the external
force, the arc-shaped connecting rods 3 are rotated relative to the
fixed platform 1. The rotation axes of three arc-shaped connecting
rods 3 are intersected with each other and each rotation axes is
parallel to the fixed platform 1. Each arc-shaped connecting rod 3
has a sliding slot 31 curved extending along a longitudinal
direction. The sliding slot 31 is arc shaped. Three connecting
shafts 21 one-to-one corresponds to the three arc-shaped connecting
rods 3 and are disposed on the movable platform 2. A first end of
each connecting shaft 21 is fixedly connected with the movable
platform 2. A second end is hinged joint with a connecting head 32.
The connecting head 32 is slid and disposed in the corresponding
sliding slot 31. In the embodiment, the movable platform 2 is
connected with the fixed platform 1 through the three arc-shaped
connecting rods 3. Thus, the movable platform 2 is disposed above
the fixed platform 1. The movable platform 2 is slid and connected
with each arc-shaped connecting rod 3. Each arc-shaped connecting
rod 3 is rotated and connected with the fixed platform 1. When one
of the three arc-shaped connecting rods 3 is rotated around its own
rotation shaft, relative to the fixed platform 1, the movable
platform 2 is driven to move by the arc-shaped connecting rod 3
through the corresponding connecting head 32 and the connecting
shafts 21. At the same time, the other two connecting shafts 21 and
the connecting heads 32 are slid along the corresponding sliding
slot 31. Since the sliding slot 31 is an arc-shaped structure, the
movable platform 2 is overturned above the fixed platform 1. The
movement is relatively simple. Namely, when one of the arc-shaped
connecting rod 3 is controlled to rotate, the movable platform 2 is
overturned in one direction around a certain point in the air. When
the different arc-shaped connecting rods 3 are controlled to
rotate, the movable platform 2 is overturned in different
directions around the certain point in the air. Because there are
three arc-shaped connecting rods 3, the movable platform 2 of the
parallel mechanism is overturned in three different directions
around the certain point in the air. In the above control mode, the
movable platform 2 is relatively stable when the movable platform 2
is overturned in any direction. The robustness and the bearing
capacity of the movable platform 2 are very good, the control
precision is high, which avoids forming accompanying movement
during overturn and has high flexibility. The structure of the
parallel mechanism is very simple and convenient to assemble.
[0023] As shown in FIG. 1 and FIG. 2, optimizing the above
embodiment, there are various structural types for the hinge joint
between the connecting head 32 and the corresponding connecting
shaft 21. For example, the connecting head 32 and the corresponding
connecting shaft 21 are connected by cross universal hinge 33. When
the moving platform 2 drives the connecting shaft 21 to overturn,
the connecting head 32 can also slide along the corresponding
sliding slot 31, it should be understood that other structural
types arc used, such as: the connecting head 32 and the connecting
shaft 21 are connected by a spherical hinge.
[0024] Furthermore, the two ends of each arc-shaped connecting rod
3 are fixedly connected with the fixed platform 1 through a
connecting component 4. The two ends of each arc-shaped connecting
rod 3 are rotated and connected with the corresponding connecting
component 4. In the embodiment, the two ends of each arc-shaped
connecting rod 3 are disposed on the fixed platform 1 by the
connecting component 4. The two ends of the arc-shaped connecting
rod 3 are rotation ends. When the arc-shaped connecting rod 3 is
driven to rotate, since the two ends are located, the rotation is
very stable, further ensuring the robustness and load bearing
capacity when the movable platform 2 is rotated.
[0025] As shown in FIG. 2 and FIG. 3, the above structure of the
connecting component 4 is detail described. Each connecting
component 4 includes two supports 41 fixedly disposed on the fixed
platform 1. The two ends of the arc-shaped connecting rod 3 both
includes a shaft hole 34 and a pin shaft 35 fixed inside the shaft
hole 34. The pin shaft 35 is rotated and connected with the
corresponding support 41. The two supports 41 of each connecting
component 4 are fixed on the fixed platform 1 by screws etc. the
other shaft hole is disposed on each support 41. The two shaft
holes of each connecting component 4 are located on a same straight
line. The fixed pin shafts 35 fixed on the two ends of the
arc-shaped connecting rod 3 respectively stick into the shaft holes
of the corresponding supports 41. The arc-shaped connecting rod 3
can rotate relative to the two supports 41. Certainly, each pin
shaft 35 and the support 41 should be located to prevent the pin
shaft 35 pulling out from the corresponding shaft hole during the
relation. Generally, the two supports 41 of each connecting
component 4 are oppositely disposed. The two ends of each
arc-shaped connecting rod 3 are both disposed between the
corresponding two supports 41. In the structural configuration, the
two ends of the arc-shaped connecting rod 3 are sandwiched between
the two supports 41, which effectively avoids the pin shaft 35 from
falling off the shaft hole of the corresponding bracket 41 during
the process of rotation. Thereby, the stability of the connection
structure between the arc-shaped connecting rod 3 and the
connecting component 4 is improved.
[0026] As shown in FIG. 1 and FIG. 2, furthermore, each connecting
component 4 corresponds to a motor 42. The motor 42 is disposed on
one of the supports 41 of the corresponding connecting component 4.
An output shaft of the motor 42 is fixedly connected with the
rotating shaft 34 at one end of the corresponding arc-shaped
connecting rod 3, or other types of transmission connections are
used between the output shaft of the motor 42 and the rotating
shaft 34. The pin roll 35 is rotated by the motor 42, thus, the
arc-shaped connecting rod 3 is overall rotated. In the embodiment,
the motor 42 is a servo motor 42, which is convenient to control
the rotation speed. The motor 42 directly is disposed on the fixed
platform 1 or fixed on the corresponding bracket 41. The motor 42
is regarded as a driving pair for the corresponding arc-shaped
connecting rod 3. The three motors 42 are respectively controlled
the rotation of the three arc-shaped connecting rods 3. The
operation is simple and the control is more flexible.
[0027] As shown in FIG. 2, furthermore, three protrusions 22 are
disposed on the movable platform 2. The three protrusions 22 and
the movable platform 2 are integrally formed and one-to-one
correspond to the three connecting shafts 21. The connecting shaft
21 is fixed and connected with the corresponding protrusion 22. In
the embodiment, when the movable platform 2 is manufactured, the
three protrusions 22 are formed on the movable platform 2. Thereby,
the movable platform 2 is fixedly connected with the three
connecting shafts 21 and the parallel mechanism is convenient to
assemble. To be specific, a threaded hole 221 is disposed at an end
of the protrusions 22 away from the movable platform 2. The
corresponding connecting shaft 21 sticks into the threaded hole 221
and the threaded connection is formed, which is convenient to
assemble and connect and make connection stability relatively high.
Generally, the movable platform 2 is a flat cylindrical shape. The
three protrusions 22 are evenly interval distribution along an
outer circular surface of the movable platform 2. Thereby, the
three connecting shafts 21 are also evenly distributed along the
outer circular surface of the movable platform 2. An angle between
the adjacent two connecting shafts 21 is 120 degrees.
[0028] The mentioned above is only the preferred embodiment of the
present disclosure, but it is not to limit the present disclosure.
Any modifications, equivalent substitutions, improvements, etc.
made within the spirit and scope of the present disclosure are
included within the scope of the present invention.
* * * * *